Motal Cheese Microbiology: The Karabakh Goatskin Bioreactor

The primary threats to cheese preservation are aerobic oxidation and the growth of common moulds (Penicillium species), which require oxygen to metabolise and degrade dairy proteins.

Packing cheese in a standard porous container or leaving it exposed to air allows oxygen to continually degrade the fats.

The motal skin solves this problem by acting as a highly efficient anaerobic micro-bioreactor.

[Salted Sheep Curd Core] ➔ Tightly Packed & Sealed ➔ [Stitched Goatskin Envelope]
↓
Rapid Consumption of Residual Oxygen by Microbes
↓
Strict Zero-Oxygen (Anaerobic) Fermentation Zone

When the damp, salted curds are forcefully compressed into the elastic, inside-out hide, the baker or shepherd systematically expels all pockets of ambient air.

Once the skin is stitched shut, the residual oxygen trapped inside the microscopic gaps of the curd mass is rapidly consumed by the initial metabolic activity of native lactic acid bacteria.

Because the skin is sealed airtight, no external oxygen can penetrate the barrier. This creates a strict anaerobic vacuum.

This zero-oxygen environment completely neutralises spoilage-causing aerobic moulds and pathogenic bacteria, establishing a pristine biochemical workspace where only specialised, beneficial anaerobic organisms can survive.

The shepherd’s myth that the skin “breathes” stems from a highly visible physical phenomenon: during the months spent underground, the exterior of the buried goatskin becomes damp and encrusted with mineral salts, yet the cheese inside never becomes waterlogged or completely desiccated.

This is a manifestation of semi-permeable membrane kinetics.

Animal skin is fundamentally a dense network of cross-linked collagen fibres. It is naturally hydrophobic on its outer surface but remains highly porous at a microscopic molecular scale.

When buried in the damp, cool earth (which maintains a steady, insulated temperature of 10 to 14°C, the skin acts as an environmental regulator:

Osmotic Pressure Regulation: The high salt content mixed into the raw curd draws free moisture out of the cheese via osmosis.

Controlled Evaporation: This extracted water moves outward through the microscopic pores of the collagen matrix.

The skin allows water vapour to slowly diffuse out into the surrounding soil, preventing the cheese from sitting in stagnant liquid and rotting.

Contamination Shield: Simultaneously, the structural density of the skin prevents the external, liquid groundwater or soil particulates from seeping in, acting as a one-way filtration valve.

As the moisture content stabilises, the true flavour of Motal Shor is forged through an intense process of enzymatic lipolysis—the biochemical breakdown of milk fats into free fatty acids.

Because the cheese is made from raw, unpasteurized sheep or goat milk, it preserves a complex matrix of native highland enzymes and wild microflora.

Locked inside the anaerobic, cool dark of the subterranean trench, these enzymes go to work on the complex triglycerides of the milk fat, cleaving them into volatile short-chain and medium-chain fatty acids:

While Motal is famously known for ageing on balconies or in cool stone cellars, there is an incredible, lesser-known traditional subterranean ageing process historically used by semi-nomadic shepherds in the Caucasus (particularly in regions like Karabakh).

When shepherds migrated between winter plains and high-altitude summer pastures (yaylaqs), carrying heavy, bulky loads of cheese was highly impractical.

Instead, they weaponised the earth as a seasonal refrigerator.

The historical underground maturation process involves several distinct phases:

1. The Buriduyk Dynamic

Before going underground, the cheese is tightly packed into the motal (the inverted animal hide skin).

Shepherds forcefully pack the curds to ensure zero air pockets remain inside.

The skin acts as a micro-porous, flexible barrier that allows moisture to wick out while preventing fresh oxygen from getting in.

2. The Transhumance Cache

Instead of hauling the filled skins back down the mountain immediately, shepherds would dig deep pits directly into the earth or hide them in specific sub-surface caches.

Because the landscape completely changes colour and foliage between spring and autumn, shepherds would carefully mark the location.

3. Anaerobic Earth Ageing

Once buried, the cheese enters a completely dark, anaerobic environment with a naturally regulated, cool temperature.

• The Microbial Action: Protected from the fluctuating outside heat, specialised ambient lactic acid bacteria and yeasts inside the skin slowly break down the proteins and fats (lipolysis and proteolysis).
• The “Axtarma” Effect: In Azerbaijani culture, this specific style of subterranean-matured cheese is called Axtarma Motal (literally “searched-for” or “foraged” Motal). Because the landscape shifts over 3–4 months, finding the buried cache in autumn was famously difficult.

4. Flavour Transformation

When dug up months later, the prolonged, cold subterranean isolation completely transforms the cheese.

The texture changes from a simple, rubbery, brined block into a crumbly, intensely savoury, and spreadable delicacy.

The flavour profile sharpens dramatically, taking on pungent, earthy notes frequently compared by culinary historians to a matured blue cheese.

While today’s commercial or modern home variants rely on controlled refrigeration or ventilated cellars, the subterranean technique remains an incredible example of ancient food preservation geography.

The relationship between the internal fur (or hair) layer of the inverted motal skin and the fermenting curd is one of the most brilliant examples of natural biochemical manipulation in ancient food preservation.

When a newcomer hears that the wool or hair side of the sheep/goat hide is folded to face the inside—directly touching the raw cheese curds—the immediate reaction is usually a mixture of confusion and hygiene anxiety.

However, this is not an accident of primitive assembly. The hair matrix is a critical chemical and mechanical component of the subterranean ageing process.

Here is the exact science behind how the internal fur layers drive the flavour, texture, and maturation of true Motal Shor:

1. The Microbial Sieve & Dynamic Fluid Drainage

Freshly packed sheep curd contains a high concentration of liquid whey. If that whey remains stagnant inside the container, the water activity ($a_w$) stays too high, creating a prime breeding ground for rot-causing anaerobic bacteria.

[Dense Milk Curd Core]
↓ (Whey Exudation)
[Interlocking Wool Fibers] ➔ Functions as a high-surface-area capillary network
↓ (Capillary Action)
[Microporous Leather Skin] ➔ Slow moisture evaporation out into the subterranean soil

The layer of short, shorn wool or hair acts as a highly effective microscopic physical drainage sieve.

Rather than allowing the wet curds to press directly flat against the non-porous leather wall (which would seal the moisture in), the interlocking fibres create an expansive, structured capillary network.

As the salted curds compress, the excess whey is drawn away from the cheese core via capillary action, wicking evenly down the length of the hairs to the porous leather hide, where it slowly evaporates outward into the cool, subterranean soil.

This leaves the interior cheese dense, crumbly, and dry enough to guarantee a long shelf life.

2. Structural Isolation (The Anti-Adhesion Shield)

If raw cheese curds are packed under high pressure against raw, bare animal skin, the gelatinous milk proteins will bond directly to the animal collagen as they dry. The cheese would literally fuse to the container.

When the shepherd tries to slice open the motal months later, the outer layer of premium cheese would rip away with the leather, destroying a significant portion of the yield.

The layer of keratin-rich hair acts as a natural anti-adhesion shield. The cheese forms a unified block within the nest of fibres, making it highly efficient to extract cleanly when the sinew stitches are cut.

3. Enzymatic Inoculation and Volatile Flavour Synthesis

The most profound impact of the internal hair layer is biochemical.

The skin and hair are not sterile; they retain a highly specific, complex ecosystem of wild, non-pathogenic yeasts and halophilic (salt-tolerant) microflora native to the mountain pastures.

• Lipase and Protease Transfer: As the warm, salted curds sit in the dark bioreactor, the moisture activates these dormant enzymes and wild yeasts embedded at the root of the hair follicles. These enzymes actively migrate into the outer layers of the cheese.
• The Pungent Profiles: These cultures accelerate proteolysis (protein breakdown) and lipolysis (fat breakdown). They cleave the milk fats into specific volatile organic molecules—such as isovaleric acid and caproic acid.

This localised enzymatic breakdown is what gives the outer edges of Motal cheese its highly sought-after, aggressively sharp, earthy aroma.

It introduces a pungent depth that textually mimics the complex development of Western cave-aged blue cheeses, entirely without the introduction of commercial mould cultures.

4. The Hygiene Paradox: Why There Is No Hair in Your Food

The ultimate worry is that the final product will be a messy, hair-filled block of dairy. This is prevented by an elegant pre-treatment of the hide:

Before the cheese is ever introduced, the raw skin is heavily cured with coarse mineral salt for up to two to three weeks.

This deep salting causes the skin cells to dehydrate and contract violently around the hair roots.

The salt physically locks the hair follicles deep into the leather matrix, making it structurally impossible for individual hairs to shed or break away into the curd.

When you open a properly cured motal, the cheese separates cleanly away from a solid, velvet-like internal hair lining, perfectly flavoured and entirely free of debris.

Motal Shor cheese does not absorb the spirit of the mountain soil; it uses an animal-hide envelope to weaponise zero-oxygen biochemistry.

The legendary immortality and sharp flavour profile of Azerbaijan’s Karabakh Motal cheese are the direct results of primitive, yet flawless, material engineering.

By sealing salted curds within a stitched, inside-out animal skin, highland shepherds create a high-efficiency anaerobic bioreactor that suffocates spoilage organisms while allowing beneficial enzymes to flourish.

The skin’s semi-permeable collagen matrix perfectly balances internal moisture loss against external soil dampness—proving that this ancient, underground delicacy is a masterwork of natural chemical preservation.